Your heart is a pump, or rather two pumps. One pumps fluid to the lungs, and the other to the rest of the body. When the pump fails, fluid backs up. This is first observed in the feet and legs, and later in the lungs. Water pills help reduce excess fluid and thereby relieve strain on the pump. Taking your water pills as prescribed in the earlier part of the day will help decrease nighttime bathroom trips. If you don’t take these pills as prescribed, you could experience worsening complications, such as swollen feet, difficulty breathing, and higher blood pressure.